Hi, yiyuan Lv.
The buttons "Clear" and "Clear All" are clean list of files on the client side.
For cleaning list of files in managed bean you can use another command button, like this example:
Yes, Vitaliy is right.
But what should I do If i want to do like this .such as a user who wants to upload some attachments in the e-mail. In this case we must have a function that when a file has already uploaded in the page it can be canceled . In the <rich:fileupload> , I can't implement this fucntion. Beacuse I can't cancel it when it is uploaded